AVS 50th International Symposium
    Magnetic Interfaces and Nanostructures Thursday Sessions
       Session MI+SC-ThM

Paper MI+SC-ThM4
Growth and Characterization of GaMnN/AlN Multiple Quantum Wells

Thursday, November 6, 2003, 9:20 am, Room 316

Session: New Spintronic Materials
Presenter: G.T. Thaler, University of Florida
Authors: G.T. Thaler, University of Florida
R.M. Frazier, University of Florida
J. Stapleton, University of Florida
C.R. Abernathy, University of Florida
S.J. Pearton, University of Florida
R.P. Rairagh, University of Florida
J. Kelly, University of Florida
A.F. Hebard, University of Florida
Correspondent: Click to Email
Though a number of recent studies have reported room temperature ferromagnetism in GaMnN, some important questions remain including determining the minimum layer thickness needed for ferromagnetic ordering.@footnote 1,2,3@ In this paper, we report on the growth and characterization of a variety of multiple quantum well structures comprised of layers of GaMnN and AlN. XRD analysis of the layers showed sharp satellite peaks indicative of good interfacial quality. By contrast to the GaMnAs system, magnetic ordering was maintained even for structures with 5nm GaMnN layer thicknesses. The magnetic moment of the GaMnN/AlN layers was determined to be ~1.7 Bohr magnetons per Mn, much higher than the 1.1 Bohr magnetons per Mn obtained in 200nm GaMnN films grown under the same conditions. This increase is believed to be due in part to improved crystallinity brought about by the presence of the AlN and also due to strain induced by the smaller lattice constant of the AlN. The use of strained superlattices has been shown to increase the activation of the deep acceptor Mg in p-GaN and p-AlGaN.@footnote 4,5@ It is likely that a similar effect is increasing the concentration of Mn+2 relative to Mn+3, resulting in a higher moment than in the thicker films. Attempts to tailor the strain, and the magnetic properties, by varying the Al content in the buffer and barrier layers will be discussed, as will the potential for using these phenomena to make magnetic strain sensors. This work was supported by the Army Research Office under: ARO-DAAD19-01-1-0701 and by NSF under: ECS-0224203 and DMR 0101856. @FootnoteText@ @footnote 1@ G.T. Thaler, et al. Appl. Phys. Lett. 80, 3964 (2002). @footnote 2@ S. Sonada, et al. J. Cryst. Growth 237-239, 1358 (2002). @footnote 3@M.L. Reed, et al. Appl. Phys. Lett. 79, 3473 (2001). @footnote 4@ Y.-L. Li, et al. Appl. Phys. Lett. 76, 2728 (2000). @footnote 5@P. Kozodoy, et al. Appl. Phys. Lett. 74, 3681 (1999). .